A former lobbyist nominated by Barnaby Joyce to sit on the board of the Murray-Darling Basin Authority attended a meeting at which a NSW government official was recorded offering her and other irrigators sensitive data.

It can be confirmed that Ms Davey was part of a teleconference in which NSW government water official Gavin Hanlon proposed handing over de-badged documents, those which are stripped of the departmental logo, to help irrigators exploit the Murray-Darling Basin Plan

"Obviously we would have to de-badge it," Mr Hanlon says of the data in the recording.

murray darling basin authority board barnaby joyce water

One lobbyist, now identified as Ms Davey, responds: "Yeah, that would be fabulous".

Federal Labor and a cross-party delegation of South Australian state and federal politicians rejected this as inadequate and nor do they accept an independent investigation ordered by the NSW government, saying the state cannot be trusted.

They are demanding a judicial inquiry and for Mr Joyce to be relieved of the Water Resources portfolio.

This clamour has intensified following confirmation of Ms Davey's attendance at the teleconference.

"When the Murray-Darling Basin Authority was first set up, Malcolm Turnbull said it would be expert and independent," said federal shadow environment minister Tony Burke.

"If there was a phone hook-up where people conspired to undo the plan, I can't see how the government can seriously say the participants should be put in charge.

"When people heard that phone hook-up on Four Corners last week they were shocked. You'd only put the participants in charge if you wanted to destroy the plan."

Ms Davey's nomination to the board was never ratified and there is no suggestion Mr Joyce knew about Ms Davey's attendance at the teleconference when he nominated her. She requested her nomination be withdrawn so as not to create any further harm or controversy.

In recommending Ms Davey, Mr Joyce cited her "extensive experience in water management, water markets, the irrigation industry and public relations and communications".

"Ms Davey has a well-grounded understanding of the Murray-Darling Basin Plan and is very experienced in stakeholder engagement regarding water policy issues in Australia."

South Australian Water Minister Ian Hunter opposed her nomination, telling Mr Joyce in writing that Ms Davey had previously lobbied for lower environmental flows down the river.

"This is a person with an agenda being put onto an authority that's in place to deliver the Murray-Darling Basin agreement – and that says to me there are ulterior motives here," he said.

"It says to me there are National Party shenanigans going on to try to undermine the plan."

The latest revelations follow a report in Sydney's The Daily Telegraph that NSW Primary Industries Minister Niall Blair, a former National Party state chairman, is trying to change the law retrospectively to justify a decision by his department to allocate more water to cotton farmer Peter Harris who is also a political donor.